How to make a course "by invitation only"
If you don't want your course to be available publicly, but would rather only students you choose be enrolled in it, follow these simple steps.
First, make sure you're in edX Studio, which looks like this:
Next, we're going to click on the "Settings" drop down menu, and choose "Advanced Settings"
From this page, scroll down to the "Invitation Only" field, and delete "false" and type "true"
After you've made any changes to the "Advanced Settings" page, don't forget to save your work.